DEPOSITION FILM, METHOD OF MEASURING SHAPE OF DEPOSITION FILM, METHOD OF CONTROLLING MANUFACTURING PROCESSES, MANUFACTURING METHOD, SHAPE MEASURING APPARATUS AND APPARATUS FOR CONTROLLING MANUFACTURING PROCESSES

Abstract: The invention provides a method of and an apparatus for measuring and controlling the position of an edge of a deposition film, positions and widths of deposition portions and margin portions, and positions of heavy edges without the need of a skilled operator. According to the invention, the deposition portions and the margin portions are formed in a stripe shape lengthwise and alternately widthwise by a margin forming apparatus and a metal deposition apparatus, and the resulting deposition film is irradiated with light from a light source while being run by a film transportation system. A line sensor camera detects a distribution of light transmittivity on the film in the widthwise direction of the film, and on the basis of the detected distribution of light transmittivity the position of an edge of the deposition film, positions and widths of the deposition portions and the margin portions, and positions of heavy edges are measured, and the margin forming apparatus and the metallic deposition apparatus are controlled on the basis of the resulting measurements.

Description: A vapor deposited film, and a geometry measuring method, production process control method, production method, geometry measuring apparatus and production process control apparatus therefor Technical Field The present invention relates to a vapor deposited strip film with vapor deposited zones and zones free from vapor deposition formed alternately in the transverse direction, and a geometry measuring method, production process control method, production method, geometry measuring apparatus and production process control apparatus for monitoring and controlling the positions of the vapor deposited zones and zones free from vapor deposition of the vapor deposited film in the transverse direction, and for producing the vapor deposited film. Prior Art For producing a vapor deposited film, an evaporating machine as shown in Fig. 16 is used. In the evaporating machine 1, a base film 12 is set on a film unwinder 11 installed in a vacuum chamber 10, and the film 12 is carried through the plurality of rollers of a carrier system 13 and a cooling roller 14, then later wound around a winder 15. While being carried, the film 12 is provided with margin zones as zones free from metal vapor deposition formed continuously in the machine direction at predetermined positions in the transverse direction by a margin forming device 16, and furthermore, has metal vapor deposited zones formed continuously in the machine direction at predetermined positions alternately with said margin zones in the transverse direction by a metal evaporator 17 installed below the cooling roller 14. In Fig. 16, symbol 18 denotes a viewing window formed in the vacuum chamber 10, and 19, a vacuum exhaust port formed in the vacuum chamber 10. As a result, as shown in the cross sectional views in the transverse direction of Figs. 17 and 18 for example, the film 12 has a vapor deposition pattern formed. In Fig. 17, the film 12 has metal vapor deposited zones 12a and zones 12b free from metal vapor deposition formed on it. In Fig. 18, heavy edges 12c thicker in vapor deposited film thickness are formed in vapor deposited zones 12a, in addition to the vapor deposited zones 12a and the margin zones 12b. The heavy edges 12c have an effect of allowing easier deposition of sprayed metal in the electrode forming step of capacitor production from the vapor deposited film. Furthermore, the margin zones 12b are formed by masking the positions corresponding to the margin zones 12b when the metal evaporated from the metal evaporator 17 is deposited on the film 12. The masking can be achieved by applying an oil or tape to the positions corresponding to the margin zones using the margin forming device 16 before metal deposition. In this step of vapor deposition, the positions and widths of the vapor deposited zones and zones free from vapor deposition in the transverse direction of the film may vary when the film carrier system or margin forming device malfunctions or when the film is uneven in thickness, and the variation greatly affects the quality of the vapor deposited film. Thus in the production of the vapor deposited film, the positions and widths must conform to specified values. For this reason, in the conventional technique, the film carrier system 13 and the margin forming device 16 must be sufficiently maintained to keep the positions and widths of the vapor deposited zones and margin zones constant. Moreover, during the step of evaporation, the operator 20 observes the vapor deposited film 12 immediately after vapor deposition through the viewing window 18, and adjusts the film carrier system 13 to keep the film 12 travelling stably and adjusts the margin forming device 16 to let the positions and widths of the margin zones conform to the specified values. If the heavy edges 12c are to be formed, they must be located at the centres of the vapor deposited zones 12a in the transverse direction of the film since the heavy edges 12c correspond with the electrode forming portions in the production of capacitors. Hence, in the conventional technique, the relative position of the margin forming device 16 and the metal evaporator 17 to form the heavy edges in the transverse direction of the film are adjusted so that the centres of the heavy edges 12c continue to correspond with the centres of the vapor deposited zones 12a held between the margin zones 12b, before metal evaporation. Furthermore, during the step of evaporation, the operator 20 observes the vapor deposited film 12 immediately after evaporation through the viewing window 18, and finely adjusts the margin forming device 16 or the metal evaporator 17 to let the central positions of the heavy edges 12c agree with the central positions of the vapor deposited zones 12a. In the above conventional technique, since the positions and widths of the margin zones are manually adjusted to conform with the specified values by the operator based on his experience, a high skill is required disadvantageously. In particular, it is not easy to train the operator so that he can make dimensional adjustment based on his recognition of slight deviations. Moreover, if the cause for the deviation in the positions and widths of the margin zones cannot be identified soon, uncontrollable deviation can occur to remarkably lower the efficiency before a skilled operator can take any effective measure. In addition, the position adjustment of the heavy edges also requires a high skill to achieve a good result. For these reasons, the vapor deposited film thus prepared is liable to be unstable in the dimensions and positions of the vapor deposited zones and vapor nondeposited zones. As a result, the capacitors, etc. to which such a vapor deposited film is applied can be very variable in electrostatic capacity or low in reliability. An apparatus for and a method of coating a length material is disclosed in EP-A-0082654. The present invention has been completed to solve the above problem. Aspects of the present invention aim to provide a geometry measuring method, production process control method, production method, geometry measuring apparatus and production process control apparatus for allowing easy production of a vapor deposited film by easily monitoring the edge positions of the film, the positions and widths of the vapor deposited zones and the margin zones, and furthermore as required, the positions of heavy edges, and controlling these positions and widths in the step of metal evaporation onto the film without requiring any skilled operator, and also to present a vapor deposited film produced by the production method. In a first aspect, the present invention presents a method for measuring the geometry of a vapor deposited film, comprising the steps of allowing a vapor deposited strip film, having vapor deposited zones and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction, to travel, while illuminating the vapor deposited film with light; receiving the light transmitted through the vapor deposited film; detecting the light transmittance distribution in the transverse direction of the vapor deposited film from the transmitted light; and determining the edge positions of the vapor deposited film, and the positions and widths of the vapor deposited zones and the vapor nondeposited zones based on the detected light transmittance distribution. The present invention also presents a method for measuring the geometry of a vapor deposited film, comprising the steps of allowing a vapor deposited strip film, having vapor deposited zones, each with a longitudinal ridge, and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction, to travel, while illuminating the vapor deposited film with light; receiving the light transmitted through the vapor deposited film; detecting the light transmittance distribution in the transverse direction of the vapor deposited film from the transmitted light; and determining the edge positions of the vapor deposited film, the positions and widths of the vapor deposited zones and the vapor nondeposited zones, and the positions of the ridges based on the detected light transmittance distribution. The present invention also presents a method for controlling a process for production of a vapor deposited film, comprising the steps of forming vapor deposited zones and zones free from vapor deposition in stripes in the longitudinal direction and alternately in the transverse direction on a travelling strip film while illuminating the vapor deposited film with light; receiving the light transmitted through the vapor deposited film; detecting the light transmittance distribution in the transversal direction of the vapor deposited film from the transmitted light; monitoring the edge positions of the vapor deposited film, and the positions and widths of the vapor deposited zones and the zones free from vapor deposition based on the detected light transmittance distribution; controlling the film in the transverse direction with reference to the monitored edge positions; and controlling the positions and widths of the vapor deposited zones and the zones free from vapor deposition with reference to the monitored positions and widths of the vapor deposited zones and the zones free from vapor deposition. The present invention also presents a method for controlling a process for production of a vapor deposited film, comprising the steps of forming vapor deposited zones, each with a longitudinal ridge, and zones free from vapor deposition in stripes in the longitudinal direction and alternately in the transverse direction on a travelling strip film while illuminating the vapor deposited film with light; receiving the light transmitted through the vapor deposited film; detecting the light transmittance distribution in the transverse direction of the vapor deposited film from the transmitted light; monitoring the edge positions of the vapor deposited film, the positions and widths of the vapor deposited zones and the zones free from vapor deposition, and the positions of the ridges based on the detected light transmittance distribution; controlling the film in the transverse direction with reference to the monitored edge positions; controlling the positions and widths of the vapor deposited zones and the zones free from vapor deposition with reference to the monitored positions and widths of the vapor deposited zones and the zones free from vapour deposition; and controlling the positions of the ridges with reference to the monitored positions of the ridges. The present invention also presents a system for measuring the geometry of a vapor deposited film in a method as claimed in the accompanying claim 1, for a film having vapor deposited zones and zones free from vapor deposition formed in stripes in the longitudinal direction and alternatively in the transverse direction, which said system comprises an apparatus comprising: a light source for emitting light to such a travelling vapor deposited strip film; a sensor for receiving the light transmitted through the vapor deposited film; a means for detecting the light transmittance distribution of the vapor deposited film in the transverse direction from the transmitted light; and electronic control means operative to calculate the edge positions and the positions and widths of the vapor deposited zones and the zones free from vapor deposition based on the detected light transmittance distribution. An embodiment of the invention in accordance with this aspect, concerns a system for measuring the geometry of a vapor deposited film in a method as claimed in the accompanying claim 2, for a film having vapor deposited zones , each with a longitudinal ridge, and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction, wherein the electronic control means is additionally operative to calculate the positions of the ridges based on the detected light transmittance distribution. The present invention also presents a system for controlling a process for production of a vapor deposited film in a method as claimed in the accompanying claim 7, for a film having vapor deposited zones and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction, which said system comprises an apparatus comprising: a carrier system for allowing such a strip film to travel continuously ; evaporator means for forming the vapor deposited zones; a margin forming device for forming the zones free from vapor deposition; a light source for emitting light to the film; a sensor for receiving the light transmitted through the film; a means for detecting the light transmittance distribution of the film in the transverse direction from the transmitted light; electronic means operative to calculate the edge positions of the film, and the positions and widths of the vapor deposited zones and the zones free from vapor deposition based on the detected light transmittance distribution; a first control means operative to control the carrier system with reference to the calculated edge positions; and a second control means operative to control the margin forming device for forming the zones free from vapor deposition with reference to the calculated positions and widths of the vapor deposited zones and the zones free from vapor deposition. An embodiment of this aspect of the present invention provides a system for controlling a process for production of a vapor deposited film in a method as claimed in the accompanying claim 8, for a film having vapor deposited zones, each with a longitudinal ridge, and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction, wherein the electronic means are operative to calculate the positions of the ridges based on the detected light transmittance distribution; and the apparatus includes a third control means for controlling the vapor deposited zone forming means with reference to the calculated positions of the ridges. In the method for measuring the geometry of a vapor deposited film of the present invention, the vapor deposited film is illuminated with light, and the distribution of light transmittance in the transverse direction of the vapor deposited film is measured. Since the outside of the edges of the film, the vapor deposited zones and zones free from vapor deposition of the film are different in light transmittance, the edge positions of the film, and the positions and widths of the vapor deposited zones and the zones free from vapor deposition, and furthermore, as required, the positions of the heavy edges can be obtained from the. light transmittance distribution. In the method for controlling a process for production of a vapor deposited film of the present invention, the position of the film in the transverse direction, and the positions and widths of the vapor deposited zones and the zones free from vapor deposition, and as required, the positions of the heavy edges are controlled with reference to the edge positions of the film, the positions and widths of the vapor deposited zones and the zones free from vapor deposition, and as required, the positions of the heavy edges, respectively monitored as described above. Therefore, the vapor deposited film of the present invention has the vapor deposited zones and margins formed stably at desired positions with accurate dimensions irrespective of the skill of the operator, and hence is small in variation in product quality and is highly reliable. Brief Description of the Drawings Fig. 1 is a drawing showing the structure of a vapor depositing machine used for producing a vapor deposited film according to the measuring method or control method of the present invention, as an example. Fig. 2 is a block diagram showing the structure of a control apparatus for the vapor depositing machine shown in Fig. 1. Fig. 3 is a drawing showing the measurement field of view by the line sensor camera shown in Fig. 1. Fig. 4 is a flow chart for illustrating the measurement and control action of the control apparatus shown in Fig. 2. Fig. 5 is a flow chart for illustrating the measurement and control action of the same control apparatus. Fig. 6 is a flow chart for illustrating the measurement and control action of the same control apparatus. Fig. 7 is a flow chart for illustrating the measurement and control action of the same control apparatus. Fig. 8 is a diagram for showing the light transmittance distribution of a base film. Fig. 9 is a list showing the data measured by the line sensor camera. Fig. 10 is a diagram showing the light transmission distribution of a film for detecting the positions of the film edges, the vapor deposited zones and the margin zones. Fig. 11 is a diagram showing the light transmittance distribution of a film for detecting the positions of heavy edges. Fig. 12 is a schematic drawing showing an application of the present invention to inspection in the step of slitting. Fig. 13 is a drawing showing the results of measurement by the line sensor camera shown in Fig. 12. Fig. 14 is an expanded view showing a partially expanded portion of Fig. 13. Fig. 15 is a diagram showing the results of Fourier analysis at a transition point from a vapor deposited zone to a margin zone shown in Fig. 13. Fig. 16 is a drawing showing a conventional vapor depositing machine. Fig. 17 is a cross sectional view of a vapor deposited film in the transverse direction. Fig. 18 is a cross sectional view of a vapor deposited film with heavy edges, in the transverse direction. The Best Mode for Carrying Out the Invention An example of the present invention is described below based on the drawings of Figs. 1 to 15. Fig. 1 is a drawing showing the structure of a vapor depositing machine, as an example, for producing a vapor deposited film using the measuring and control methods of the present invention. The same components as shown in the vapor depositing machine of Fig. 16 are given the same symbols for convenience of explanation. Furthermore, in this example, the margin zones are formed by partially applying an oil to the film before vapor deposition, and the heavy edges are formed by partially increasing the amount of evaporation from the metal evaporator. In Fig. 1, the components different from those of the vapor depositing machine shown in Fig. 16 are a light source 21 installed near the predetermined position of the film carrier system 13 in the vacuum chamber 10, and a line sensor camera 22 installed near the viewing window 18 for detecting the light transmitted through the film 12 when the film 12 is illuminated with the light from the light source 21. As the control apparatus of the vapor depositing machine adopting the measuring and control methods, it is desirable to use an electronic control unit (hereinafter called "ECU") 23 such as a personal computer shown in Fig. 2, for performing the detection of light signals from the light source 21 by the line sensor camera 22, measuring the positions of the film edges 12d, the vapor deposited zones 12a, the margin zones 12b and the heavy edges 12c of the film 12 for every specified length, and for storing measured values. In this example, the ECU 23 is connected to the film carrier system 13, the margin forming device 16 and the metal evaporator 17 containing the heavy edge forming device, of the vapor depositing machine 1, respectively through interfaces 24 to 26. Furthermore, the ECU 23 is connected to the line sensor camera 22 through an 8-bit analog/digital (hereinafter called "A/D") converter 27 and an interface 28. The ECU 23 delivers control signals to said respective components 13, 16 and 17 based on the measured values sent from the line sensor camera 22 in order that the film may travel stably, that the positions and widths of the vapor deposited zones 12a and the margin zones 12b may conform to the specified values, and that the centres of the heavy edges 12c may agree with the centres of the vapor deposited zones 12a. Moreover, the ECU 23 is connected to an encoder 29 through an interface 30, to take in a film length signal from the encoder 29. In addition, the ECU 23 is connected also to a volatile memory 31 and a nonvolatile memory 32. The volatile memory 31 is used for high speed data processing of measured values, and the nonvolatile memory 32 is used for storing data. The number of pixels of the line sensor camera 22, the focal distance of the lens and the distance between the line sensor camera 22 and the vapor deposited film 12 are not especially limited, and can be selected to suit the measurement field of view and the resolution decided with reference to the film width, vapor deposition width and margin width of the vapor deposited film 12 to be measured. It is preferable that the number of pixels of the line sensor camera 22 is 500 or more and that the clock frequency is 1 MHz or more. In this example, the line sensor camera 22 is a camera with CCD elements and delivers data to the ECU 23 through the 8-bit A/D converter 27 and the interface 28, and furthermore has control signals for action applied from the ECU 23 through the interface 28. This example adopts 300 mm as the width W of the film 12 to have a metal vapor deposited, 2048 as the number of pixels of the CCD elements of the line sensor camera 22, 28.672 mm as the length of the elements, 782.3 mm as the distance between the vapor deposited film 12 and the CCD elements, 409.6 mm as the width of the measurement field of view in the film transverse direction and 0.2 mm in measurement resolution (width of measurement field of view per one pixel). Thus, the width of the measurement field of view is about 100 mm wider than the width of the vapor deposited film to be measured, and the position of the line sensor camera 22 is adjusted to let the centre of the measurement field of view agree with the centre of the vapor deposited film. Therefore, in this example, both the edges of the film are included in the measurement field of view (see Fig. 3). The above width of the measurement field of view and the measurement resolution are theoretical, and the actual values are usually slightly different from the theoretical values since the focal distance of the lens, the distance between the vapor deposited film 12 and the CCD elements, etc. include errors for the rated values. Therefore, for highly accurate measurement, the positions and widths of the vapor deposited zones and the zones free from vapor deposition obtained by deciding the actual measurement resolution must be calibrated. To meet this necessity, a test pattern with stripes known in dimension can be placed at the position of the vapor deposited film 12 for measurement to obtain the number of CCD pixels of the line sensor camera 22 corresponding to the stripe pitch, so that the stripe pitch may be divided by the number of CCD pixels, to decide the accurate measurement resolution. However, this method requires a test pattern to be placed for setting the measurement resolution, to increase the work volume, and since vapor deposition cannot be effected during the work, productivity cannot be sufficiently enhanced. Thus, the inventors paid attention to the fact that the means for forming the margin zones is manufactured mechanically highly accurately, and devised a method for setting the measurement resolution in-line during production. That is, in the case of an oil margin method, oil is sprayed onto the film from small holes formed at certain intervals in a pipe called a margin nozzle, to form the margin zones. The intervals of the small holes are established mechanically highly accurately. Thus, even if the relative position between the film and the margin nozzle changes, the intervals between the margin zones formed on the film remain constant and equal to the intervals between the small holes formed in the margin nozzle. Therefore, the intervals between the formed margin zones agree with the intervals between the small holes equal to the nominal forming intervals. Furthermore, also in the case of a tape margin method, the intervals of tape support means are predetermined mechanically accurately. Therefore, as in the case of the oil margin method, the intervals between the formed margin zones agree with the intervals between the tape support means equal to the nominal forming intervals. This characteristic of margin zone formation is used to accurately predetermine the actual measurement resolution from the correlation between the measured intervals between margin zones and the nominal forming intervals between margin zones. In this example, the light transmittance distribution of the vapor deposited film 12 in the transverse direction is measured in the beginning of vapor deposition or during production, and-the number of CCD pixels of the line sensor camera 22 corresponding to each interval between the margin zones is obtained. Then, the known interval between the small holes formed in the margin nozzle is divided by this number of CCD pixels. In this case, in view of correction of camera installation error, etc., it is preferable to obtain the numbers of CCD pixels of the line sensor camera corresponding to a plurality of intervals between the margin zones rather than obtaining the number of CCD pixels of the line sensor camera 22 corresponding to one interval between margin zones, for using their mean value. An interval between margin zones is predetermined by the interval between the number given to the pixel at which the change from a margin zone to a vapor deposited zone takes place and the number given to the pixel at which the change from the next margin zone to the next vapor deposited zone takes place. More preferably, it is predetermined with reference to the central positions of the respective margin zones (the central position means the mean position between the position of the pixel at which the change from a vapor deposited zone to a margin zone takes place and the position of the pixel at which the change from that margin zone to the next vapor deposited zone takes place). In the case of the oil margin method, the margin width may depend on the distance between the margin nozzle and the film, but the central position does not change. So it is preferable to predetermine the interval between the margin zones based on the central positions of the respective margin zones. Either of the above methods can enhance productivity without requiring the troublesome work of setting a test pattern. Furthermore, even during production, in-line calibration can be effected for contribution also to the security of measurement accuracy. The transmission light source 21 must be DC lighting or high frequency lighting. In the case of high frequency lighting, the lighting frequency with reference to the light signal integrating time T int of the line sensor camera is desirably (1/T int ) x 10 or more. If the transmission light source 21 used is constant in the quantity of light in the film transverse direction and all the pixels of the line sensor camera 22 are equal in sensitivity, then the light intensity distribution detected by the line sensor camera 22 can be treated like the light transmittance distribution. If the light source 21 is irregular in light quantity or if the pixels of the line sensor camera 22 are different in sensitivity, correction is necessary. The correction can be effected as follows. If the light intensity detected by each pixel with light directly acquired from the light source 21 without the film 12 is P 0 (n) (n is a given pixel number) and the detected intensity of each pixel with the film 12 placed between the light source 21 and the line sensor camera 22 is P(n), then the corrected intensity P'(n) is P' (n) = k x P(n)/P 0 (n), where k is a constant. P'(n) can be treated like the corresponding intensity in the light transmission distribution. This example uses, as shown in Fig. 3, a fluorescent lamp of 500 mm in the length of the light emitting portion as the light source 21 and it lights at a high frequency of 30 KHz from 10 mm behind the film face. When the film edges, the vapor deposited zones and the margin zones are measured using the line sensor camera 22 and the light source 21, the light signal integrating time of the line sensor camera and the opening of the camera lens should be such that the signal detected by the line sensor camera in the absence of the film is kept in a range from 40 to 100%, preferably 60 to 90% of the intensity with which the CCD elements of the camera is saturated. Subsequently, if the signal intensity in the absence of the film is P b , the signal intensity of the margin zone is P f and the signal intensity of the vapor deposited zone is P m , then the threshold level TH f for detecting the film edges and the threshold level TH m for detecting the borders between the vapor deposited zones and the margin zones should be set as follows: TH f = P f + k f x (P b - P f ) TH m = P m + k m x (P f - P m ) where k f and k m are constants to be set in a range from 0.2 to 0.8, preferably 0.4 to 0.6. On the other hand, also in the measurement of the heavy edges, the difference in light transmittance between a heavy edge and a portion other than the heavy edge in the vapor deposited zone is used. Also the light transmittance in a portion other than the heavy edge in a vapor deposited zone is smaller than that in a margin zone by a factor of more than decades, and the light transmittance at a heavy edge is further smaller. Therefore, if the opening of the line sensor camera lens and the light signal integrating time are the same as in the above case of measuring the film edges, the vapor deposited zones and the margin zones only, the signals detected by the line sensor camera at heavy edges and in portions other than the heavy edges in the vapor deposited zones are small. As a result, due to the influence of noise, etc., it is difficult to distinguish heavy edges from portions other than the heavy edges in the vapor deposited zones. Thus, in order to allow discrimination between the heavy edges and the other portions than the heavy edges in the vapor deposited zones, studies were made to enlarge the signals of the vapor deposited zones detected by the line sensor camera. As a result, it was found that if the light quantity taken in by the line sensor camera for the measurement of heavy edge positions is smaller than that for the measurement of film edges, vapor deposited zones and margin zones by a factor of 5 or less, the signals of even the portions other than the heavy edges in the vapor deposited zones detected by the line sensor camera are small, and it is difficult to accurately obtain the heavy edge positions, that if the light quantity taken in by the line sensor camera is larger by a factor of 100 or more, the CCD elements of the line sensor camera may be saturated even at the light intensity at the heavy edges, undesirably not allowing the heavy edge positions to be obtained, and as a result, that the light quantity taken in by the line sensor camera for the measurement of heavy edges can be set in a range from 5 to 100 times that for measuring the film edges, vapor deposited zones and margin zones. The light quantity taken in by the line sensor camera can be set in a range from 5 to 100 times by either enlarging the opening of the lens or elongating the light signal integrating time. Compared with enlarging the opening of the lens mechanically, elongating the light signal integrating time does not require any mechanical factor, and is hence advantageous for the measurement with the light quantity changed several times in a short time. Therefore, for measurement of heavy edges, the light signal integrating time of the line sensor camera is set in a range from 5 to 100 times that for measuring the film edges, vapor deposited zones and margin zones. To obtain the heavy edge positions from the light transmittance distribution thus detected, a threshold level can be set as in the case of measuring the film edges, vapor deposited zones and margin zones, but if the light transmittances at the centres of the heavy edges are least, the central positions of the heavy edges can be obtained from the minimum values in the light transmittance distribution. In this example, the lens opening of the line sensor camera is set at F = 5.6, and the light signal integrating time T int of the line sensor camera for detecting the film edges, vapor deposited zones and margin zones is set at 1 msec., while the light signal integrating time of the line sensor camera for detecting the heavy edge positions is set at 32 msec. With reference to the flow charts of Figs. 4 to 7, the action of the control apparatus shown in Fig. 2 is described below. At first in Fig. 4, if the operator enters an instruction to start measurement, the program contained starts, and the ECU 23 asks the operator to enter the conditions required for measurement and control (step 101). The conditions required to be entered include whether heavy edges to be measured exist, the desired margin width W m0 and the data take-in intervals 1. If all the conditions in step 101 have been entered, the ECU 23 takes in measured data from the line sensor camera 22 through the A/D converter 27 and the interface 28. Then, the ECU 23 graphs the measured data and presents the graph on a display not illustrated (step 102). When the data are taken in, the measured data form the light transmittance distribution of a base film as shown in Fig. 8 since metal evaporation does not start yet. At this time, the light signal integrating time of the line sensor camera 22 is T int = 1 msec., and the P b and P f levels shown in Fig. 8 correspond to the signal intensity in the absence of the film and the signal intensity of the margin zones as described above. Subsequently the operator recognizes the graph and sets the threshold level TH f for detecting the film edges and the threshold level TH m for detecting the borders between the vapor deposited zones and the margin zones based on formulae (1) and (2) as shown in Fig. 8 (step 103). The value of P m in formula (2) cannot be known from Fig. 8, but since P m is smaller than P f by more than a factor of decades, the formula (2) can be regarded as TH m = k m x P f without any problem. If the threshold levels TH f and TH m are set, the ECU 23 recognizes the threshold levels TH f and TH m , and waits for the start of metal evaporation (step 104). The judgment of evaporation start by the ECU 23 is effected with reference to the signal generated when the shutter to shut off the metal vapor is opened. That is, the time when the shutter is opened to cause the metal vapor to be deposited on the film face is judged as the start of evaporation. If the start of metal evaporation is judged based on the result of calculation, the ECU 23, in Fig. 5, takes in the vapor deposited film length (hereinafter called "vapor deposited length") L from the encoder 29 (step 105), and judges whether the vapor deposited length L is a number integer times that of the data take-in interval 1 set in step 101 (step 106). If the vapor deposited length L is not a number integer times the take-in interval 1, the ECU 23 waits until the vapor deposited length L becomes a number integer times the take-in interval 1. If the vapor deposited length L is a number integer times the take-in interval 1, the ECU 23 takes in measured data from the line sensor camera 22 (step 107). In this case, the number of pixels of the line sensor camera 22 is 2048, and the output of the A/D converter 27 is 8 bits. Thus, the measured data are taken in as data of 2048 x 8 bits by the ECU 23 (see Fig. 9). Subsequently, the ECU 23 examines all the 2048 pixels as to whether the measured value of each pixel is larger or smaller than the threshold level THf set in step 103 for detecting the film edges. In this case, the relation between the measured value and TH f is examined in the order from the smallest pixel number "0" (to the left in the field of view) to the largest pixel number "2047" (to the right in the field of view). The first pixel number N fd (a pixel number out of 0 to 2047) at which the measured value becomes smaller than TH f is detected as the left edge of the film, and the first pixel number N fu (a pixel number out of 0 to 2047) at which the measured value becomes larger than TH f is detected as the right edge of the film, to be respectively stored in the volatile memory 31 (step 108). If the measurement of heavy edges is not set in step 101, the light transmittance distribution of the film obtained by the measured data of the respective picture elements is as shown in Fig. 10, and the positions of the pixel numbers N fd and N fu are as shown in the diagram. That is, Fig. 10 shows a case where the positions of the film edges, vapor deposited zones and margin zones are detected. The actual positions of both the edges of the film (in mm) are obtained by multiplying the_measured values of the pixel numbers N fd and N fu by a measurement resolution of 0.2 mm. In the above description, the first pixels at which the measured value becomes smaller or larger than the threshold level TH f are identified as the positions of the edges, but if the data of the two adjacent pixels which are on both sides of TH f are used for interpolation to obtain the corresponding edge position, more highly accurate measurement can be effected preferably. The interpolation using the two adjacent pixels should be preferably effected also for detecting the transition points between the margin zones and the vapor deposited zones described below. After detecting the edge positions of the film, the ECU 23 examines all the pixels between N fd and N fu as to whether the measured value of each pixel taken in at step 107 is smaller or larger than the threshold level TH m for detecting the borders between the vapor deposited zones and the margin zones set at step 103. Also in this case, as in the case of detecting the edge positions of the film, the relation between the measured value and TH m is examined in the order from the smallest pixel number to the largest pixel number. The pixel number N md (a pixel number of 0 to 2047) at which the measured data becomes smaller than TH m is detected as a transition point from a margin zone to a vapor deposited zone, and the pixel number N mu (a pixel number of 0 to 2047) at which the measured value becomes larger than TH m is detected as a transition point from a vapor deposited zone to a margin zone, respectively to be recorded in the volatile memory 31 (step 109). When a plurality of vapor deposited zones and a plurality of margin zones exist in the full width of the film, the pixels of the borders are called N md (1), N mu (1), N md (2), N mu (2), ... N md (n), N mu (n) (n is a given integer), in this order from the smallest pixel number, and recorded in the volatile memory 31. In the case of Fig. 10, since there are four vapor deposited zones, there are also four pixels each detected. The actual transition point (in mm) between a vapor deposited zone and a margin zone is obtained by multiplying the measured value at the pixel number N md or N mu by a measurement resolution of 0.2 mm. Then, in Fig. 6, the ECU 23 judges whether heavy edges exist (step 110). This judgment is based on whether the existence of heavy edges was set at step 101. If the heavy edges exist for example, the ECU 23 takes steps in succession from step 111. If the heavy edges do not exist, the ECU 23 takes steps from step 115, disregarding the steps 111 to 114. That is, if the heavy edges exist at step 110, the ECU 23, first of all, changes the light signal integrating time of the line sensor camera 22 to 32 msec., and subsequently takes in the measured data from the line sensor camera 22 after a lapse of 32 msec. or more (step 111). The light transmittance distribution obtained from the measured data taken in is, for example, as shown in Fig. 11. The ECU 23 detects the positions of the heavy edges from the distribution. In this case, it is also possible to detect the positions of the heavy edges using a threshold value as in the detection of the film edges, etc. The detection of heavy edge positions is intended to let the centres of the heavy edges agree with the centres of the vapor deposited zones and to keep the heavy edge thickness distribution and the light transmittance distribution symmetrical in the transverse direction of the film. Therefore, in this example, the pixel numbers N HB (pixel numbers out of 0 to 2047) at the bottoms of the downward peaks shown in Fig. 11 are detected. When a plurality of vapor deposited zones exists in the full width of the film, as many heavy edges as exist are called N HB (1), N HB (2), ... N HB (n) in this order from the smallest pixel number, and recorded in the volatile memory 31 (step 112). In the case of Fig. 11, since the number of the vapor deposited zones is four, the number of the pixel numbers detected is also four. Thus, in this example, in the above steps, the positions of the film edges, the positions of the vapor deposited zones and the margin zones (transition points between the vapor deposited zones and the margin zones) and the positions of the heavy edges are obtained as measured data. The ECU 23 can use the measured data for calculating the difference between the central position of each heavy edge and the central position of the corresponding vapor deposited zone, the distances of the vapor deposited zones and the margin zones from each film edge, and the widths of the vapor deposited zones and the margin zones. For example, if the leftmost vapor deposited zone is the 1st zone, and the vapor deposited zones located on the right of it are the 2nd to n-th (n is an integer) zones, then the difference D c (n) in mm between the central position of the heavy edge of the n-th vapor deposited zone and the central position of the n-th vapor deposited zone can be calculated from D c (n) = {N HB (n) - (N md (n) + N mu (n))/2} x 0.2. The ECU 23 records the result of calculation in the volatile memory 31 (step 113). The ECU 23 delivers a control signal to the metal evaporator 17, to stabilize the result of calculation D c (n) at "0", for letting the central position of the heavy edge agree with the central position of the vapor deposited zone (step 114). The width W c (n) of the n-th vapor deposited zone in mm can be calculated from W c (n) = (N mu (n) - N md (n)) x 0.2, and the ECU 23 records the result of calculation in the volatile memory 31 (step 115). Furthermore, the distances in mm from the film edges to the transition points between the vapor deposited zones and the margin zones and to the central positions of the heavy edges can be obtained by subtracting N fd from the respective measured values of N md , N mu and N HB in the case of distances from the left film edge, or subtracting the respective measured values from N fu in the case of distances from the right film edge; and multiplying the differences by 0.2. The results of calculation are recorded in the volatile memory 31 (step 116). The ECU 23 delivers a control signal to the film carrier system 13 based on the data of the film edge positions detected at step 108 (measured values of pixel numbers N fd and N fu ), to control the film carrier system 13, for letting the film travel stably with a certain range without any deviation in the transverse direction (step 117). Moreover, the ECU 23 delivers a control signal to the margin forming device 16 based on the data of transition points between the vapor deposited zones and the margin zones detected at step 109 (measured data of pixel numbers N md and N mu ) and the width data W c (n) of the vapor deposited zones obtained at step 115, to control the margin forming device 16 for minimizing the position change of the vapor deposited zones and the margin zones and for stabilizing the widths of the vapor deposited zones and the margin zones at the desired values (step 118). In this example, if the margin forming device 16 uses a margin nozzle as in the oil margin method, the positions of the vapor deposited zones and the margin zones are controlled by adjusting the margin nozzle in the film transverse direction. Furthermore, the ECU 23 controls the margin forming device 16 to keep constant the distance between the oil spouts of the margin nozzle and the film face for maintaining the widths of the vapor deposited zones and the margin zones constant (if the distance between the oil spouts and the film face is larger, the widths of the margin zones become larger). Subsequently, the ECU 23 judges whether all the vapor deposition has been completed (step 119), and if the vapor deposition is not completed, the ECU 23 returns to step 105, to repeat the above measurement and control for every specified length in the film machine direction. If the vapor deposition has been completed, the ECU 23 transfers the contents (the measured values obtained for every specified length of the vapor deposited film) stored in the volatile memory 31 into the nonvolatile memory 32, to store it there (step 120), for completing its action. The completion of vapor deposition is judged with reference to the signal generated when the shutter of the metal evaporator 17 is closed. Thus, in this example, since the ECU controls the film carrier system, the margin forming device and the metal evaporator based on the respective measured data detected by the line sensor camera, no skilled operator is required, and the positions of the film edges, the positions and widths of the vapor deposited zones and the margin zones and the positions of the heavy edges can be easily controlled. The length of the film required for adjusting the positions and widths of the margin zones and the positions of the heavy edges is 990 m on average in the conventional technique, but is only 510 m on average in this example. Therefore, in the case of a 32000 m long film, the yield can be enhanced by 1.5% in this example compared to the conventional technique, and even though the margin failure rate is 1% in the conventional technique, it is 0% in this example. Thus, a yield enhancement of 2.5% can be achieved as a whole. Furthermore in this example, since the adjustment in the step of vapor deposition is automatic, the adjustment requires less time, to increase the production accordingly, for further enhancing the yield. Moreover in this example, since the measured values are stored in the nonvolatile memory, the stored contents can be analyzed to allow process analysis in the step of vapor deposition. Specific analysis methods include the Fourier transformation, statistical processing, etc. of the temporal changes in the positions of film edges, and the positions and widths of the vapor deposited zones and the margin zones. In process analysis, if measurement only is effected without control at steps 114, 117 and 118, the characteristics of the respective apparatuses in the vapor depositing machine are reflected in the measured values.Thus, if the measured values are analyzed, the abnormal portions of the apparatuses can be found and identified early. This example is concerned with the measurement and control of the positions of the vapor deposited zones and the zones free from vapor deposition in a film to have a metal vapor deposited in a vapor depositing machine, but the present invention is not limited thereto or thereby, and can also be applied to the inspection in the step of slitting downstream of the step of vapor deposition. Fig. 12 is a schematic drawing showing a case of inspection in the step of slitting. The differences in the drawing from the above example are that data measurement only is effected, that the distance between the face of the vapor deposited film 12 and the CCD elements of the line sensor camera 22 is 500 mm, that the measurement resolution is 0.116 mm and that the measurement field of view is 237 mm. Furthermore, in this particular example, the vapor deposited film is free from heavy edges, and the film set on a film unwinder 11 is transported at 200 m/min. by a film carrier system 13, then later wound by a winder 15. In this operation, measurement is effected 8192 times during a travel of 200 m length, so the measurement intervals are 200/8192 m. Fig. 13 shows the results of measurement by the line sensor camera 22. In the drawing, symbol 12a denotes a vapor deposited zone; 12b, a margin zone; and 12d, the left edge of the film. In this case, since the resolution consists of 8192 scanning lines in the film longitudinal direction and 2048 pixels in the film transverse direction (camera's measurement field of view), part of Fig. 13 can also be expanded as shown in Fig. 14, for detailed observation. This view shows that the left edge 12d of the film and the transition points between the vapor deposited zones 12a and the margin zones 12b fluctuate in cycles of about 0.7 m. The Fourier analysis of the transition points from the vapor deposited zones 12a to the margin zones 12b gives the diagram shown in Fig. 15. In Fig. 15, frequency components of 1.7 Hz and 4.8 Hz are detected, and from these values and the film travelling speed of 200 m/min., it can be seen that the transition points fluctuate in position in cycles of 1.96 m and 0.69 m. This suggests that there is some malfunctioning of parts of the vapor depositing machine or slitter corresponding to the cycles. Apart from the Fourier analysis, statistical analysis can give the results as shown in Tables 1 to 3. Table 1 shows the results of analysis at the points detected by the line sensor camera. Analysis of points (absolute values) detected by line sensor camera Item No. Mean value (mm) Min. value (mm) Max. value (mm) Standard deviation Film edge : 8.44 7.7x5 9.13 0.48 Margin zone 1: 13.17 12.83 13.53 0.09 2: 18.61 18.38 18.73 0.07 → Vapor deposited zone 3: 119.14 118.96 119.31 0.06 Vapor deposited zone →Margin zone 1: 14.75 14.57 14.91 0.07 2: 3: 115.22 216.58 115.15 216.42 115.38 216.77 0.07 0.08 Analysis of distances from film edge Item No. Mean value (mm) Min. value (mm) Max. value (mm) Standard deviation Margin zone 1: 4.73 3.93 5.55 0.47 2: 10.17 9.48 10.87 0.48 → Vapor deposited zone 3: 110.70 109.95 111.45 0.47 Vapor deposited zone 1: 6.31 5.66 6.94 0.47 2: 106.78 106.13 107.52 0.47 → Margin zone 3: 208.14 207.41 208.91 0.47 Table 2 shows the results of analysis on the distances from a film edge. Analysis of vapor deposited zone widths, margin zone widths and L Item No. Mean value (mm) Min. value (mm) Max. value (mm) Standard deviation Vapor deposited zone 1: 1.58 1.16 1.73 0.08 2: 96.61 96.53 96.77 0.06 3: 97.44 97.34 97.58 0.06 Margin zone 1: 3.87 3.82 3.93 0.06 2: 3.91 3.82 3.93 0.04 L : 100.53 100.47 100.70 0.06 Table 3 shows the results of analysis on the widths of the vapor deposited zones, the widths of the margin zones and the vapor deposited length L. Therefore, in this example, these values can be used as inspection data of the vapor deposited films. Industrial Applicability The geometry measuring method, production process control method, production method, geometry measuring apparatus and production process control apparatus for a vapor deposited film of the present invention can be preferably used for the production of a vapor deposited film with vapor deposited zones and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction such as a metal vapor deposited film for capacitors. Furthermore, the vapor deposited film of the present invention is highly accurate in the dimensions and positions of the vapor deposited zones and the zones free from vapor deposition, and also the ridges if additionally formed. Therefore, if it is used as a film for capacitors, the capacitors obtained are less variable in electrostatic capacity and high in reliability.

Claims: A method for measuring the geometry of a vapor deposited film, comprising the steps of allowing a vapor deposited strip film, having vapor deposited zones and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction, to travel, while illuminating the vapor deposited film with light; receiving the light transmitted through said vapor deposited film; detecting the light transmittance distribution in the transverse direction of the vapor deposited film from the transmitted light; and determining the edge positions of said vapor deposited film, and the positions and widths of said vapor deposited zones and said zones free from vapor deposition based on the detected light transmittance distribution. A method according to claim 1 for measuring the geometry of a vapor deposited film, for a vapor deposited strip film having vapor deposited zones, each with a longitudinal ridge, and zones free from vapor deposition formed in stripes in the longitudinal direction and alternately in the transverse direction, which method includes determining the edge positions of the vapor deposited film, the positions and widths of the vapor deposited zones and the zones free from vapor deposition, and the positions of the ridges based on the detected light transmittance distribution. A method for measuring the geometry of a vapor deposited film, according to claim 1 or 2, wherein the measurement is effected for every specified length of the vapor deposited film. A method for measuring the geometry of a vapor deposited film, according to claim 1 or 2, wherein two threshold levels are set for the light transmittance distribution, to determine the edge positions of the vapor deposited film and the positions and the widths of the vapor deposited zones and the zones free from vapor deposition. A method for measuring the geometry of a vapor deposited film, according to claim 2, wherein after determining the positions of the ridges, the transmitted light quantity received is set at 5 to 100 times that used for determining the edge positions and the positions and widths of the vapor deposited zones and the zones free from vapor deposition. A method for measuring the geometry of a vapor deposited film, according to claim 2, wherein the measured positions and widths are calibrated based on the correlation between the change in the detected light transmittance distribution and the nominal forming intervals of the zones free from vapor deposition. A method for controlling a process for production of a vapor deposited film, comprising the steps of forming vapor deposited zones and zones free from vapor deposition in stripes in the longitudinal direction and alternately in the transverse direction on a travelling strip film while illuminating the vapor deposited film with light; receiving the light transmitted through the vapor deposited film; detecting the light transmittance distribution in the transverse direction of the vapor deposited film from the transmitted light; monitoring the edge positions of the vapor deposited film, and the positions and widths of the vapor deposited zones and the zones free from vapor deposition based on the detected light transmittance distribution; controlling the film in the transversal direction with reference to the monitored edge positions; and controlling the positions and widths of the vapor deposited zones and the zones free from vapor deposition with reference to the monitored positions and widths of the vapor deposited zones and the zones free from vapor deposition A method according to claim 7 for controlling a process for production of a vapor deposited film, which method includes providing each vapor deposited zone with a longitudinal ridge, and wherein the monitoring step includes monitoring the positions of the ridges based on the detected light transmittance distribution; and the controlling step includes controlling the positions of the ridges with reference to the monitored positions of the ridges. A system for measuring the geometry of a vapor deposited film in a method as claimed in claim 1, for a film (12) having vapor deposited zones (12a) and zones free from vapor deposition (12b) formed in stripes in the longitudinal direction and alternately in the transverse direction, which said system comprises an apparatus comprising: a light source (21) for emitting light to such a travelling vapor deposited strip film (12); a sensor (22) for receiving the light transmitted through the vapor deposited film (12); a means (23,27,28) for detecting the light transmittance distribution of the vapor deposited film in the transverse direction from the transmitted light; and electronic control means (23) operative to calculate the edge positions (12d) and the positions and widths of the vapor deposited zones (12a) and the zones free from vapor deposition (12b) based on the detected light transmittance distribution. A system according to claim 9, for measuring the geometry of a vapor deposited film in a method as claimed in claim 2, for a film (12) having vapor deposited zones (12a), each with a longitudinal ridge (12c), and zones free from vapor deposition (12b) formed in stripes in the longitudinal direction and alternately in the transverse direction, wherein the electronic control means (23) is additionally operative to calculate the positions of the ridges (12c) based on the detected light transmittance distribution. A system for controlling a process for production of a vapor deposited film in a method as claimed in claim 7, for a film (12) having vapor deposited zones (12a) and zones free from vapor deposition (12b) formed in stripes in the longitudinal direction and alternately in the transverse direction, which said system comprises an apparatus comprising: a carrier system (13) for allowing such a strip film (12) to travel continuously; evaporator means (17) for forming the vapor deposited zones (12a); a margin forming device (16) for forming the zones free from vapor deposition (12b); a light source (21) for emitting light to the film (12); a sensor (22) for receiving the light transmitted through the film (12); a means (23,27,28) for detecting the light transmittance distribution of the film in the transverse direction from the transmitted light; electronic means (23) operative to calculate the edge positions (12d) of the film, and the positions and widths of the vapor deposited zones (12a) and the zones free from vapor deposition (12b) based on the detected light transmittance distribution; a first control means (23,24) operative to control the carrier system (13) with reference to the calculated edge positions (12d); and a second control means (23,25) operative to control the margin forming device (16) for forming the zones free from vapor deposition (12b) with reference to the calculated positions and widths of the vapor deposited zones (12a) and the zones free from vapor deposition (12b). A system according to claim 11, for controlling a process for production of a vapor deposited film in a method as claimed in claim 8, for a film (12) having vapor deposited zones (12a), each with a longitudinal ridge (12c) and zones free from vapor deposition (12b) formed in stripes in the longitudinal direction and alternately in the transverse direction, wherein the electronic means (23) are operative to calculate the positions of the ridges (12c) based on the detected light transmittance distribution; and the apparatus includes a third control means (23,26) for controlling the vapor deposited zone forming means (17) with reference to the calculated positions of the ridges. A method for producing a vapor deposited film, comprising the steps of allowing a film to travel while forming vapor deposited zones and zones free from vapor deposition on the film in stripes in the longitudinal direction of the film and alternately in the transverse direction; detecting the light transmittance distribution of the film in the transverse direction; monitoring the edge positions of the film, and the positions and widths of the vapor deposited zones and the zones free from vapor deposition based on the detected light transmittance distribution; and controlling the vapor deposited zones and the zones free from vapor deposition at predetermined positions on the film with reference to the monitored edge positions and the monitored positions and widths of the vapor deposited zones and the zones free from vapor deposition.

Inventors: TORIKAI JUN, YATSUSHIRO TUGIO, TORIKAI, JUN, YATSUSHIRO, TUGIO
Applicants: TORAY INDUSTRIES, TORAY INDUSTRIES, INC.
Application year: 1994
Main classification: C23C14
IPC codes: C23C14, G01B11